Chitosan/anionic surfactant microparticles synthesized by high pressure spraying method for removal of phenolic pollutants Research Article

Biopolymeric microparticles were prepared by rapid expansion of high pressure CO2-chitosan (Chi) solution in sodium bis-(2-ethyl hexyl) sulfosuccinate (AOT) solution. At pressures higher than 2 MPa, ultrafine particles were formed while under this value, wires were obtained. The formation of Chi/AOT complex was confirmed by Fourier Transform Infrared (FTIR) Spectroscopy, whereas scanning electron microscopy was used to characterize the morphology, size and shape of the particles. The FTIR spectrum proved the interaction between the sulfonate groups of AOT and the amino groups of Chi. Microparticles are quasi-spherical in wet conditions and irregular after freeze drying, presenting a rough surface with many pores. Lyophilized hydrophobic microparticles were used to remove phenol and o-cresol from aqueous solution, and the adsorption process showed a maximum efficiency in the 7-8 pH range. The uptake of phenol and o-cresol increased with the amount of particles and decreased with increasing the pollutant concentration. The adsorption occurred rapidly in the first 60-120 minutes, and leveled off thereafter.